The long-term objective of this project is to investigate the structure and function of a specific lipoprotein gene in the cockerel. The mRNA for a major VLDL protein, apo-VLDL-II, will be purified to homogeneity. A (3H)cDNA will be synthesized, and used as a hybridization probe to quantify the amount of apoVLDL-II mRNA in the liver under various hormonal manipulations both in vivo and in liver cells in culture in vitro. A double-stranded cDNA (ds cDNA) will be synthesized and inserted into the plasmid pBR322 and amplified. The cloned apoVLDL-II DNA will be characterized by restriction mapping and sequencing. The nick-translated cloned DNA fragment will be used as a tool to partially purify the natural apoVLDL-II gene. The natural gene fragment(s) will then be purified by cloning in the lambda phage system. The cloned natural gene will be further characterized by restriction mapping, sequencing and by electron microscopy. We will also search for the presence of intervening insert sequences in the natural gene. The nick-translated insert sequences will be used to characterize the primary apoVLDL-II transcript in the avian liver in vivo and in vitro. A knowledge of the structure and function of the apoVLDL-II gene will help us better understand the pathogenesis of the various hyperlipoproteinemias, some of which are intimately related to atherosclerosis.